Gravitational-wave transient detection and multi-messenger
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Gravitational-wave transient detection and multi-messenger astrophysics Ray y Frey, y, Universityy of Oregon g for the LIGO GO Scientific Sc e t c Collaboration Co abo at o and the Virgo Collaboration LIGO-G1000515 LIGO G1000515 • Introduction – overview and status of LIGO and Virgo • Observational results • A new astronomyy with advanced GW detectors G1000515 19July2010 TeVpa, Paris 1 Required GW Sensitivity for Detection • GW emission requires time varying quadrupole moment of mass distribution distribution, → gravitational-wave strain, h = δL/ L, is the analog of the radiation field E in E&M • Strain estimate: G1000515 19July2010 TeVpa, Paris 2 GW Interferometer principle • • • • • Michelson interferometer with Fabry-Perot cavity arms. Long baseline: 4 km ( h = δL/ L ) - For h ≈10 10-21, L ≈ 1 km, then δL ≈ 10-18 m Fabry-Perot Cavity storage time ∼1 ms (∼100 bounces) Power recycling (x30) Noise estimate: 5W 10 kW G1000515 19July2010 TeVpa, Paris 3 Global network of interferometers LIGO GEO 600m 4 km & 2 km VIRGO 3 km TAMA 300m → LCGT ! LSC: LIGO+GEO AIGO- R&D LIGO 4 km → “LIGO A t li ” ? Australia” G1000515 19July2010 TeVpa, Paris 4 S5/VSR1 sensitivity 2007 LIGO Run S5: 2005-07 Ran at design sensitivity for initial LIGO Virgo Run VSR1: 2007 Data sharing g with LIGO/GEO LIGO S5 2006 S6 2007 Virgo VS R1 2008 G1000515 2009 R2 Adv LIGO 2010 19July2010 R3 2011 TeVpa, Paris 2012 2013 2014 2015 Adv Virgo 5 The LIGO-Virgo network: sky coverage LIGO O Hanford averrage antenn na factor h(t) = Fx hx(t) + F+ h+(t) Virg go ave erage anten nna factor F+ ⊕ Fx + GRBs in S5/VSR1 G1000515 19July2010 TeVpa, Paris 6 GW signals classification unmodeled matched filter Short duration Long duration Burst search Stochastic search Inspiral search CW search Credit: NASA/CXC/ASU/J. Hester et al. G1000515 19July2010 TeVpa, Paris 7 S5/VSR1 sensitivity to compact p binary y coalescence • NS-NS, NS-BH, BH-BH • Efficient GW radiators: ~10-2 Mc2 • Matched filter analysis for low-mass inspirals (horizon= distance to optimally oriented and located binary which gives SNR=8 in one detector) G1000515 19July2010 TeVpa, Paris 8 S5/VSR1 sensitivity to GW Bursts • short (< 1s) transients • unmodeled waveforms • CCSNe, GRBs, SGRs, … t (ms) EGW ≈ π 2c 3 G 2 D 2 f 02 hrss G1000515 19July2010 TeVpa, Paris 9 LIGO-Virgo Search Results • No GW detections yet • However, H b beginning i i tto make k astrophysically t h i ll iinteresting t ti lilimits it This talk: Astrophysically targeted transient searches (GRBs, SGRs) Others: • Crab pulsar spindown limit (ApJ 683 (2008) 45 ) • cosmic GW background limit < BBN (Nature 460 (2009) 990 ) • Era of advanced GW detectors is approaching (>2014) in which we expect GW detections will become frequent (more on this later) • To take advantage of this opportunity, we have developed a suite of multi-messenger lti pathways th to t fully f ll explore l th the science i (thi talk) (this t lk) G1000515 19July2010 TeVpa, Paris 10 Multi-messenger astronomy with GWs EM , neutrinos External Triggers Follow Ups GW G1000515 19July2010 TeVpa, Paris 11 Multi-messenger astronomy with GWs • • • • • • G1000515 Detection confidence Event time Sky position Improved search sensitivity Redshift g information Progenitor 19July2010 TeVpa, Paris 12 Multi-messenger astronomy with GWs – Status • Externally triggered searches – gamma, X-rays (Swift, Fermi, IPN) GRBs GRB SGRs • Externally triggered searches – neutrinos High-energy neutrinos (Ice Cube, ANTARES, …) • GRBs, ? Low-energy neutrinos (Super-K, LVD, Borexino,…) • Core-collapse supernovae • Electromagnetic follow-ups follow ups of GW triggers Requires fast (~10 min) id and distribution of LIGO-Virgo trigger (for S6) • ~few degree resolution with LIGO-Virgo network Swift ToO – XRT Wide-angle optical telescopes (SkyMapper, TAROT, Quest, …) Radio G1000515 19July2010 TeVpa, Paris 13 Multi-messenger astronomy with GWs – Status • Externally triggered searches – gamma, X-rays (Swift, Fermi, IPN) GRBs GRB Past and ongoing searches SGRs • Externally triggered searches – neutrinos High-energy neutrinos (Ice Cube, Antares, …) • GRBs, ? Low-energy neutrinos (Super-K, LVD, Borexino,…) • Core-collapse supernovae • Electromagnetic follow-ups follow ups of GW triggers Requires fast (~10 min) id and distribution of LIGO-Virgo trigger (for S6) • ~few degree resolution with LIGO-Virgo network Swift ToO – XRT Wide-angle optical telescopes (SkyMapper, TAROT, Quest, … ) Radio G1000515 19July2010 TeVpa, Paris 14 Gamma-ray Bursts and GWs Long duration GRBs Long-duration BATSE • Associated with core-collapse of massive stars (“hypernovae”) GSFC Both progenitor models would also give GW emission Short-duration GRBs • Associated with binary mergers (NS NS NS (NS-NS, NS-BH) BH) • Mergers are efficient GW radiators EGW ~ 10-2 Mc2 • Massive core collapse – unknown, but expected to be less efficient G1000515 19July2010 TeVpa, Paris 15 GRB 070201 • GRB 070201 – a short-duration gamma ray burst with position gamma-ray consistent with M31 (Andromeda), 0.8 Mpc away. • Such a nearby GRB would have easily been observed by LIGO if due to a binary merger • This hypothesis ruled out at ~99% CL Revised error box M Mazets et al., l A ApJ J 680 680, 545 4 • Most likely: SGR in M31 (Eiso~1045 erg) • Astrophys. J. 681 (2008) 1419 G1000515 19July2010 TeVpa, Paris 16 GRB 070201 (contd) Binary coalescence exclusion: Also searched for unmodeled bursts: Unable to exclude SGR from M31 G1000515 19July2010 TeVpa, Paris 17 Search for GWs from SGRs • Soft Gamma Repeaters are thought to be magnetars – highly magnetized neutron stars • Can emit occasional EM flares (~1042 erg), giant flares (~1046 erg), or flare “storms” • Flare mechanism (crust cracking) would excite vibrational modes → GWs General idea: Look for GW in coincidence with flares + flare ◊ giant flare ∗ G1000515 19July2010 TeVpa, Paris storm 18 SGRs (contd) • Search for long-lived quasiperiodic GWs after giant flare SGR 1806-20 GW energy limits are comparable to total EM energy emission PRD 76 (2007) 062003 (LSC) • Search for GW bursts at times of 190 flares from 1806-20, 1900+14 Excess power search for neutron star f-modes (~1.5–3 kHz) and arbitrary lower-frequency bursts GW energy limits as low as few × 1045 erg; PRL 101 (2008) 21110 • Stack GW signal power from each flare in 2006 SGR 1900+14 “storm”: Swift, SGR1900+14 storm 30 s 0 GW energy limit li i few f × 1045 erg; ApJ A J 701 01 (2009) L68 L68. G1000515 19July2010 TeVpa, Paris 19 Advanced GW detectors LIGO S5 2006 S6 2007 Virgo VS R1 2008 2009 R2 GEO HF 2010 R3 2011 2012 2013 Adv LIGO 2014 2015 Adv Virgo Install Advanced LIGO Advanced LIGO and Virgo • Major upgrades Lasers Lasers, optics optics, suspensions Limited by Quantum noise • 10x better sensitivity • 1000x bigger search volume Some elements of advanced detectors implemented already in S6 and VSR3 G1000515 19July2010 TeVpa, Paris 20 Multi-messenger astronomy with GWs – current developments • Externally triggered searches – gamma, X-rays (Swift, Fermi, IPN) GRBs GRB SGRs • Externally triggered searches – neutrinos High-energy neutrinos (IceCube, ANTARES, …) • GRBs, ? Low-energy neutrinos (Super-K, LVD, Borexino,…) • Core-collapse supernovae • Electromagnetic follow-ups follow ups of GW triggers Requires fast (~10 min) id and distribution of LIGO-Virgo trigger (for S6) • ~few degree resolution with LIGO-Virgo network Swift ToO – XRT Wide-angle optical telescopes (SkyMapper, TAROT, Quest, …) Radio G1000515 19July2010 TeVpa, Paris 21 High-energy neutrinos + GW • High-energy neutrinos possible from GRBs: baryons accelerated in relativistic shocks Long GRBs Short GRBs Failed GRBs Low-L GRBs y • Joint data analysis planned: LIGO-Virgo + IceCube, ANTARES (e.g. (e g Y Y. Aso Aso, et al CQG 25 (2008) 114039 ) See Poster by B. Bouhou G1000515 19July2010 TeVpa, Paris 22 Multi-messenger astronomy with GWs – current developments • Externally triggered searches – gamma, X-rays (Swift, Fermi, IPN) GRBs GRB SGRs • Externally triggered searches – neutrinos High-energy neutrinos (Ice Cube, ANTARES, …) • GRBs, ? Low-energy neutrinos (Super-K, LVD, Borexino,…) • Core-collapse supernovae • Electromagnetic follow-ups follow ups of GW triggers Requires fast (~10 min) id and distribution of LIGO-Virgo trigger (for S6) • ~few degree resolution with LIGO-Virgo network Swift ToO – XRT Wide-angle optical telescopes (SkyMapper, TAROT, Quest, …) Radio G1000515 19July2010 TeVpa, Paris 23 Core-collapse supernovae • Classic multi-messenger astronomical events: Gravitational Waves (prompt) Neutrinos (prompt, 10s of MeV, 3 flavors) Electromagnetic (delayed) • Optical (EM) signature: may be obscured (eg SN 2008iz in M82 missed in optical) unable to determine time of bounce to better than ~ day • Neutrinos and GWs directly probe physics of core collapse Signatures separated by < seconds A tight coincidence window can be used to establish a correlation Sensitivity range of current GW and neutrino detectors similar C. D. Ott, A. Burrows, L. Dessart, and E. Livne. Astrophys. J., 685, 1069, 2008. G1000515 19July2010 TeVpa, Paris 24 Core-collapse SNe (contd) • Classic core bounce GW burst • Perhaps: acoustic pulsations of proto-neutron star A. Burrows, E. Livne, L. Dessart, C. D. Ott, and J. Murphy. Astrophys. J., 655, 416, 2007. G1000515 19July2010 TeVpa, Paris 25 CCSNe (contd) • Neutrinos: Super-K: ~104 detected neutrinos for galactic SN ~1 1 ffor M31 Next generation (larger) detectors proposed g agreements g for jjoint GW-neutrino • Currentlyy pursuing searches • GW range very uncertain (need detections to understand the physics!) • Comparable range for aLIGO/AdV and Super-K (local group) with weak signals for extragalactic SNe – coincidence helpful f (I. Leonor et al CQG 27 (2009) 084019 ) • Rate: 5 Mpc sensitive range gives ~1 CCSN / 2 y (Ando 2005) G1000515 19July2010 TeVpa, Paris 26 Multi-messenger astronomy with GWs – current developments • Externally triggered searches – gamma, X-rays (Swift, Fermi, IPN) GRBs GRB SGRs • Externally triggered searches – neutrinos High-energy neutrinos (Ice Cube, Antares, …) • GRBs, ? Low-energy neutrinos (Super-K, LVD, Borexino,…) • Core-collapse supernovae • Electromagnetic follow-ups follow ups of GW triggers Requires fast (~10 min) id and distribution of LIGO-Virgo trigger (for S6) • ~few degree resolution with LIGO-Virgo network Swift ToO – XRT Wide-angle optical telescopes (SkyMapper, TAROT, Quest, …) Radio G1000515 19July2010 TeVpa, Paris 27 EM Followups • First attempts with LIGO-Virgo network Dec, 2009 p Aug-Sept g p 2010 • More expected G1000515 19July2010 TeVpa, Paris 28 Advanced LIGO/Virgo reach (example) NS-NS coalescence reach BNS sources ∼ Dn n = 2.7 → 3 D ~ 50 M Mpc, iinitial iti l LIGO/Virgo p , Adv ~ 500 Mpc, LIGO/Virgo Advanced detectors reach includes millions of large galaxies and hundreds of superclusters G1000515 19July2010 TeVpa, Paris 29 Binary coalescence expected rates arXiv: 1003.2480 (LSC, Virgo) G1000515 19July2010 TeVpa, Paris 30 GWs, GRBs, Cosmology • Advanced LIGO/Virgo is sensitive to coalescing NS and/or BH binaries to distances which are cosmologically relevant. • The detected waveform is a function of many quantities, including: • A sample of short GRBs with measured redshifts allow extraction of Di t Distance (DL) independent i d d t off EM di distance t lladder dd (based (b d only l on GR) e.g. Dalal et al, PRD 74 (2006) 063006: measure Ho to 2% in a year of Advanced LIGO data (too optimistic?) • Sky position ( θ, φ) and beaming constraint ( ι ) improve measurement of DL Nissanke Ni k ett al,l arXiv:0904:1017 Xi 0904 1017 G1000515 19July2010 TeVpa, Paris 31 Summary • LIGO and Virgo have accumulated substantial data sets at the design sensitivity of the initial detectors (runs S5 and VSR1) No detections yet, but starting to make interesting statements: • GRBs, SGRs (and others) • Current data taking and analysis: Runs S6/VSR2 • Advanced LIGO and Virgo are being constructed x10 10 b better sensitivity; ii i x1000 1000 llarger volume l ffor sources Science turn on ~2015 routine → GW science & astronomy • Expect detections to become “routine” GWs can provide unique information toward understanding the astrophysics underlying transient sources • To fully exploit this science, a suite of multi-messenger techniques have been developed (EM external triggers), while others are now being g developed p and tried ((neutrinos,, EM follow-ups) p ) G1000515 19July2010 TeVpa, Paris 32 Antenna Pattern GWs are transverse, with x and + polarizations: hx(t) , h+(t) “×” polarization Detector response “+” polarization RMS sensitivity h(t) = Fx hx(t) + F+ h+(t) G1000515 19July2010 TeVpa, Paris 33 What Limits Sensitivity of the Interferometers? • Seismic S i i noise i & vibration ib i limit at low frequencies • Thermal noise of suspensions and test masses • Quantum nature of light g (Shot Noise) limits at high frequencies • Limitations of facilities much lower G1000515 19July2010 TeVpa, Paris 34 Science runs and sensitivity Run S1 # days 17 Sept ‘02 S2 59 Feb 03-Apr 03 S3 70 Nov 03-Jan 04 S4 30 Feb- March 05 S5 N 05 – Sep Nov S 07 2y (1y (1 coincident) G1000515 19July2010 TeVpa, Paris 35 Test Masses Fused Silica, 10 kg, 25 cm diameter and 10 cm thick Polished to λ/1000 (1 nm) G1000515 19July2010 TeVpa, Paris 36 Length readout and control G1000515 19July2010 TeVpa, Paris 37 Coalescing Compact Binaries NS-NS, BH-BH, (BH-NS) binary systems Matched filter G1000515 Template-less 19July2010 TeVpa, Paris Matched filter 38 Numerical relativity NS-NS, BH-BH, (BH-NS) binary systems Development of a numerically stable formalism formalism… F. Pretorius, PRL 95 (2005) X BH-BH, 10:1 mass ratio, arXiv:0811.3952 LSC+theory “NINJA”: arXiv:0901.4399 G1000515 19July2010 TeVpa, Paris Baker, et al 2008 PRD 78 044046 39 Advanced LIGO SILICA 180 W PRM BS ITM ETM SRM PD 830 kW Power Recycling Mirror Beam Splitter Input Test Mass End Test Mass Signal Recycling Mirror Photodiode otod ode G1000515 19July2010 TeVpa, Paris 40
